1. Field
The present invention relates to a self-undercut expansion anchor system meant to be used for the insertion and setting of anchors, such as sleeve type and anchor bolt wedge type anchors into brittle materials such as concrete, stone, masonry and cementuous materials.
2. Background
Anchors are conventionally used in construction to attach various components of a building construction to an overhead ceiling or other structure. Such components to be attached can relate to, for example, services that provide plumbing, electrical, drainage, sprinkler system piping and drop ceilings. From these anchors, which are usually of the sleeve type or wedge type variety, all of the above services and ceilings are suspended or secured.
Conventionally, in setting anchors in concrete to suspend an awning, for example, a hole is pre-drilled in the surface to which the anchor is to be applied, and then the anchor is inserted into the pre-drilled hole. However, when setting such anchors in concrete it is not uncommon for such anchors to weaken and loosen over time, particularly in situations where cracking or chipping of the concrete around the pre-drilled hole has occurred.
Furthermore, studies have revealed that cracking can typically occur in the concrete element, and that such cracks can significantly impact the performance of anchors. Cracks can originate on a concrete beam or slab in a variety of ways, such as creep, temperature settlement of the support or foundation, thermal expansion and contraction stress overload, or from a natural disaster such as an earthquake or flood. In such situations, the situation can arise where, if one such concrete anchor fails and lets go, the remaining anchors, by virtue of the weight they additionally assume in light of such failure, can also similarly collapse and fail.
It has been found that enlarging the lower (interior) part of the pre-drilled hole can allow for the use of anchors in a more secure manner. It has further been found that providing a pre-drilled hole with an enlarged, conical lower end can be advantageously provided by a drill bit having enlarged cutters adjacent the tip, which is inserted into the pre-drilled hole, whereby the enlargement of the cutters is configured so that it can pass through the shaft of the pre-drilled hole to the upper end to be enlarged.
It would therefore be advantageous to have an improved self-undercut expansion anchor system meant for use in a pre-drilled hole for the insertion and setting of anchors into brittle materials such as concrete, stone, masonry and cementuous materials.
It would be further advantageous to have an improved self-undercut expansion anchor system for use in creating a drill hole and, at the same time, enlarging a lowermost end of a drill hole, wherein an anchor can later be positioned and securely retained within the enlarged area.
It would also be further advantageous to have an improved self-undercut expansion anchor system meant to be used for the later insertion and setting of anchors which utilizes interlocked components which can be used as a setting tool in a one-step process to position a bore hole sleeve and an anchor in position within the bore hole. To this end, the present invention effectively addresses this need.